Golf club with interchangeable shaft

ABSTRACT

A golf club with an interchangeable shaft that allows conventional shafts to be inserted into a golf club head. An adaptor is securely attached to the bottom end of the shaft. The adaptor is screwed into the hosel on the golf club head. A spacer element is positioned between the adaptor and the hosel to provide a surface against which the adaptor is tightened. A set screw passes through the hosel to securely hold the adaptor and shaft in place within the club head and keep the shaft from rotating with respect to the club head.

I. FIELD OF THE INVENTION

This invention relates to golf clubs and more particularly to a golf club having an interchangeable golf club shaft by which any of a plurality of golf club shafts can be installed in the club head.

II. BACKGROUND AND SUMMARY OF THE INVENTION

Improvements in golf clubs enable golfers to customize their clubs to their particular swing. For example, modifications in the angle of the shaft to the club face can adjust the loft or the lie of the club. Similarly, different shafts have different characteristics that are better suited to a particular swing. Shafts are made from different materials, with the most popular being steel or graphite with different amounts of flex that are better suited for a given swing speed. Golf clubs that allow a player to easily change the shaft while utilizing the same club head allow a player to easily change the characteristics of a golf club without necessarily purchasing a completely new set of clubs.

Applicant's invention allows the player to easily change the playing characteristics of the golf club by changing the shaft attached to the club head. A standard diameter shaft is used eliminating the necessity for using specially manufactured shafts. The shaft has an adaptor mounted to the distal or bottom end of the shaft. The adaptor is threaded on the outside. The hosel on the golf club head has an internal bore that has complementary threads to threadedly receive the adaptor. The adaptor is screwed into the hosel so that the adaptor and the shaft are securely received into the club head. A spacer ring made of a softer metal than the hosel is placed between the hosel and a collar on the adaptor so that the adaptor is screwed down tightly against the spacer rather than against the hosel. This allows the shaft to be unscrewed when the shaft is to be changed. The shaft extends into the head so that it maintains the same feel and playability as a standard attached shaft. A set screw passes through the hosel and locks against the adaptor to securely retain the shaft in the club head.

III. OBJECTS AND ADVANTAGES

It is an object of the present invention to provide a golf club with interchangeable golf shafts. It is a related object to provide a golf club that uses a golf club shaft with an adaptor attached to its distal end, the adaptor received in the golf club head.

It is another object to provide a golf club in which the golf club shaft can be unscrewed from the golf club head and replaced with another golf club shaft having different characteristics.

Yet another object is to provide a golf club with an interchangeable shaft that uses a spacer between the adaptor and the hosel on the golf club head so that the adaptor is securely tightened against the spacer rather than directly against the golf club head.

Still another object is to provide a golf club that has a set screw passing through the hosel to secure the shaft mechanically within the golf club head.

IV. DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view with portions removed of the inventive golf club illustrating the various components including the shaft, club head, adaptor, spacer and set screw.

FIG. 2 is a front elevation view of the adaptor.

FIG. 3 is a cross sectional view of the adaptor and hosel with portions removed showing the shaft removed from the adaptor and the adaptor screwed against the spacer into the hosel, and the set screw screwed into the hosel.

FIG. 4A is a cross sectional view with portions removed of an alternate embodiment in which the shaft is at an angle with respect to the longitudinal axis of the adaptor to increase the lie of the golf club head.

FIG. 4B is a cross sectional view with portions removed of another alternate embodiment in which the shaft is at an angle with respect to the longitudinal axis of the adaptor to decrease the lie of the golf club head.

V. DESCRIPTION OF THE PREFERRED EMBODIMENT

Turning first to FIG. 1, there is illustrated the first embodiment of a golf club 10 of the present invention. There is a conventional shaft 12 that is preferably made of steel or graphite. The shaft 10 has an upper or grasping end 14 and a bottom or distal end 16. The diameter of the shaft is also of conventional design, with the bottom or distal end having a constant diameter.

A club head 18 can be a wood, iron, hybrid or any other golf club head as the invention is not restricted to being used on any one particular golf club head. The club head has a top portion 20, a toe, 22, a face 24, a heel 26, and a bottom 28. There is a hosel 30 extending up from the top portion where it joins with the heel 26. The hosel 30 has a diameter “D” that is greater than those of conventional golf clubs as will be described later.

The hosel 30 has a bore 32 with interior threads 34. There is a top 36 which defines the end of the hosel and its length above the top portion 20 of the club head 18. Preferably the bore 32 extends from the top 36 into the club head 18 beyond the top portion 20.

An adaptor 40 provides the interface between the shaft 12 and the hosel 30. The adaptor is preferably made of metal, but it can be made of hard plastic or other suitable material having the desired characteristics to accomplish the purpose of an interface piece. Looking at FIGS. 2 and 3, the adaptor 40 is substantially cylindrical in design. There is a passageway 41 extending from a top portion 42 to a bottom portion 50. There is a pair of opposite flats 44 on the top portions 42 to provide a surface which can easily be engaged by a wrench or pliers. Below the top portion 42 is a center cylindrical portion 46 which has exterior threads 48. Below the center portion 46 is the cylindrical bottom portion 50.

As seen in FIG. 3 there is a shoulder 52 in the bottom portion 50 of the passageway 41. A stop 54 is inserted into the passageway 41 through the top portion 42 and pushed down to the shoulder 52 where it provides a fixed bottom plate.

The golf club 10 is assembled as follows. The distal end of the shaft 16 is inserted through a tapered sleeve 55 which provides a clean transition from the top portion 42 of the adaptor 40 to the shaft 12. This is not required to practice the invention, but gives an aesthetically pleasing look to the finished club. The distal end 16 is then inserted into the passageway 41 in top portion 42 of the adaptor 40. A small amount of glue or adhesive is placed in the passageway 41 or on the distal end of the shaft 16. This helps in securely retaining the shaft in the adaptor, yet can be loosened by a skilled club maker to insert a different shaft. The distal end 16 is pushed into the adaptor 40 until the distal end 16 engages the stop 54. This completes the assembly of the adaptor onto the end of the shaft.

A spacer 56, which is a circular ring with a central hole, is placed over the bottom portion 50 of the adaptor. The central hole is slightly larger than the diameter of the center portion 46 of the adaptor so that the spacer can be slid up over the bottom portion 50, past the center portion 46 and up to the top portion 42. There is a ledge 58 separating the top portion 42 and the center portion 46. The ledge 58 provides a shoulder which the spacer 56 engages and is secured against, and restricts any further lateral movement of the spacer 56 along the adaptor 40.

The club head as illustrated in FIG. 1 is a right handed club. Normally one would expect the adaptor 40 with the shaft inserted into it, to be screwed into the hosel by turning the shaft clockwise, such as required with right handed threads. However, the exterior threads 48 and the complementary interior threads 34 are left handed threads. This means that the shaft 12 is rotated counter clockwise in order to screw the adaptor into the hosel 30. The shaft 12 is rotated until the ledge 58 on the top 42 securely engages the spacer 56 against the top of the hosel 36. In this manner the spacer, which is preferably made of a softer metal than the adaptor or the hosel, absorbs the force of tightening. This allows the shaft to be more easily unscrewed when it is desired to change shafts. If one were to have a hard metal interface between the adaptor and the hosel, such as if the adaptor ledge 58 and the hosel 30 were both made of titanium or steel, then it would be extremely difficult to unscrew the two pieces after the golf club was used. The reason is that with left handed threads, each time the club strikes a ball, the impact transmits a tightening force to the adaptor. With the soft metal spacer 56 between the hosel and the adaptor, the spacer provides a shock absorber and interface which restricts the ultimate tightening forces between the adaptor and the hosel. In the case of a left handed club, the threads on the adaptor and the hosel will be right handed threads.

A mechanical securing means is provided in order to assist in securing the adaptor 40 in the hosel 30. As seen in FIGS. 1 and 3, there is a hole 62 radially disposed in the hosel 30. The hole 62 is threaded and receives a set screw 64. Once the adaptor 40 is screwed into the hosel 30 to the fullest extent, the set screw 64 is turned and tightened against the center portion 46 of the adaptor 40. To release the adaptor 40 from the hosel 30, the set screw is merely reversed and unscrewed from engaging the center portion 46.

In order to align the adaptor with the hosel when fully inserted, an indicator mark 66 is placed on the adaptor. A complementary indicator mark 68 is placed on the hosel. When the shaft 12 is properly and completed screwed into the hosel 30, the two indicator marks, 66, 68 will be in alignment. The indicator marks also can be used to properly align a golf club grip on the shaft 12 with the club head 18.

As can be seen, the shaft is of standard design and dimensions. For this reason, the passageway 41 of the adaptor must be properly dimensioned to receive the distal end 16 of the shaft 12. The diameter of the center portion 46 will be greater than the diameter of the distal end 16. Furthermore the diameter of the bore 32 in the hosel 30 will be the same as the diameter of the center portion 46. This allows the use of standardly available shafts. When the adaptor 40 is screwed into the hosel 30, the distal end 16 of the shaft 12 extends into the body of the golf club head 18. This allows the golfer to have the same feeling as a conventionally mounted shaft. Furthermore the weight of the adaptor 40 is negligible so there is not substantial weight addition to the golf club 10.

In the alternate embodiment as seen in FIGS. 4A and 4B, the lie of the club can be adjusted. If a golfer tends to not place his hands or body in the proper position, it is possible that the bottom 28 of the club 18 will not lie flat on the ground. In order to compensate for this, it is possible to use a modified adaptor 40. As seen in FIG. 4A, the hosel 30 has a center line 70 which runs longitudinally through the center of the hosel. However, the passageway 41 is not formed along the center line of the adaptor. Instead it is offset by a predetermined amount in order to compensate for the players swing. Generally this will be one or two degrees. This is illustrated in FIGS. 4A and 4B as the angle between lines 70 and 72 which represent the center line of the hosel and the center line of the passageway. As seen, the lie of the club 18 can be varied by increasing the lie by two degrees as illustrated by arrow “B” in FIG. 4A and decreasing the lie by two degrees as illustrated by arrow “C” in FIG. 4B.

In order to make sure that the lie is properly adjusted, the shaft is screwed into the hosel so that the indicator marks 66, 68 are aligned. This will insure that the club face is perpendicular to the direction which the player desires to hit the ball. Other angles can be formed in the adaptor 40 to accommodate the golfer.

Thus there has been provided a golf club with an interchangeable shaft that fully satisfies the objects and advantages set forth herein. While the invention has been described in conjunction with a specific embodiment, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, it is intended to embrace all such alternatives, modifications and variations as fall within the spirit and scope of the appended claims. 

1. A golf club comprising: a golf club head having a top portion, a heel end, a toe end, a face, a bottom and a hosel extending up from the top portion, the hosel having an open top and an internally threaded bore, the bore extending longitudinally through the hosel for providing a passageway into the golf club head, an adaptor having a top, a center portion and a bottom, a ledge disposed between the top and center portion, at least a portion of the adaptor having exterior threads for threadedly engaging the internally threaded bore for connecting the adaptor to the hosel, the adaptor having a central passageway extending from the top to the bottom of the adaptor, a golf club shaft having a distal end received in the central passageway, mechanical locking means for retaining the adaptor in the threaded bore, and spacer means disposed between the open top of the hosel and the ledge on the adaptor for providing an interface between the hosel and the ledge against which the adaptor is tightened when screwing the adaptor into the hosel.
 2. The golf club of claim 1 wherein the golf club is a right handed golf club and the exterior threads on the adaptor are left handed threads causing the adaptor to tighten against the spacer means during swinging of the golf club.
 3. The golf club of claim 1 wherein the adaptor and head are made of metals selected from the group of titanium, titanium alloys, steel and steel alloys and the spacer is made of softer metal.
 4. The golf club of claim 1 wherein the mechanical locking means comprises a threaded passageway extending through a wall of the hosel and into the threaded bore, a screw having complimentary threads and received into the threaded passageway, the screw engaging in locking relationship the adaptor.
 5. The golf club of claim 1 and further comprising an adhesive for securing the golf club shaft in the central passageway.
 6. The golf club of claim 1 and further comprising a stop at the bottom of the adaptor for providing a stopping point which the shaft cannot extend beyond when the shaft is received in the central passageway.
 7. The golf club of claim 1 wherein a portion of the central passageway in the adaptor extends from the top of the hosel into the golf club head whereby the golf club shaft extends into the golf club head when the adaptor is screwed into the hosel and engages the spacer means.
 8. The golf club of claim 1 wherein the distal end of the shaft is a constant diameter and the central passageway is of constant diameter to receive the distal end.
 9. The golf club of claim 1 wherein the golf club is a left handed golf club and the exterior threads on the adaptor are right handed threads causing the adaptor to tighten against the spacer means during swinging of the golf club.
 10. A golf club comprising: a golf club head having a body with a top portion, a heel end, a toe end, a face and a bottom, the body having a hosel with an open top end and a bore, at least a portion of the bore being threaded, the bore having a length extending from the open end to the body, a golf club shaft having a proximal end and a distal end, an adaptor having an open top, an outside wall and a central passageway for receiving the distal end of the golf club shaft, the adaptor further having exterior threads for threadedly engaging the threaded portion of the bore, the adaptor having a length longer than the hosel's length so that it extends into the body when fully inserted into the hosel, mechanical locking means engaging the adaptor for retaining the adaptor in the bore, means disposed between the adaptor and the hosel for providing an interface member against which the adaptor and hosel can be tightened to securely attach the adaptor to the body.
 11. The golf club of claim 10 wherein the bottom of the golf club head rests on a flat horizontal surface and the golf club shaft when mounted in the hosel defines a lie angle with respect to the flat horizontal surface.
 12. The golf club of claim 12 wherein the central passageway has a longitudinal axis that is offset by a predetermined angle with respect to the outside wall of the adaptor for adjusting the angle of the golf club shaft with respect to the hosel thereby changing the lie angle.
 13. The golf club of claim 13 wherein the longitudinal axis is offset by an angle with respect to the outer wall of the adaptor by ½ degree to 2½ degrees.
 14. The golf club of claim 10 and wherein the means disposed between the adaptor and the hosel for providing an interface comprises spacer means disposed the open top end of the hosel and the adaptor.
 15. The golf club of claim 10 wherein the mechanical locking means comprises a threaded passageway extending through a wall of the hosel and into the threaded bore, a screw having complimentary threads and received into the threaded passageway, the screw engaging in locking relationship the adaptor.
 16. The golf club of claim 15 wherein the adaptor and head are made of metals selected from the group of titanium, titanium alloys, steel and steel alloys and the spacer is made of softer metal.
 17. The golf club of claim 15 wherein the golf club is a right handed golf club and the exterior threads on the adaptor are left handed threads causing the adaptor to tighten against the spacer means during swinging of the golf club.
 18. The golf club of claim 10 and further comprising an adhesive for securing the distal end of the golf club shaft in the central passageway.
 19. The golf club of claim 10 and further comprising a stop at the bottom of the adaptor for providing a stopping point which the shaft cannot extend beyond when the shaft is received in the central passageway.
 20. The golf club of claim 15 wherein a portion of the central passageway in the adaptor extends from the top of the hosel into the golf club head whereby the golf club shaft extends into the golf club head when the adaptor is screwed into the hosel and engages the spacer.
 21. The golf club of claim 15 wherein a portion of the central passageway in the adaptor extends from the top of the hosel into the golf club head whereby the golf club shaft extends into the golf club head when the adaptor is screwed into the hosel and engages the spacer. 